Value can go up, but when the demand totally outstrips supply and it becomes hard to find bitcoin to make one's payment, good chance something else (without this lack of liquidity) steps in and whatever is left of bitcoin loses all value as it's not used any more. This assuming a digital currency will ever become a serious player, of course.

Considering there's some master file where all the movement of all bitcoin and fractions of it are stored, I wonder what's up with these bitcoin. It should be possible to trace these bitcoin: from the people that lost them, the wallet of MtGox can be traced. And then it can be traced whether they're still in that wallet.

And then? If a wallet is lost, the bitcoin is lost forever? No way to re-mine it or anything? Because this would be bad for the future of bitcoin. 7% disappeared with the demise of MtGox. A large number got lost to some UK garbage belt. More will be lost to whatever causes. Over time there may be no bitcoin left!

Wrong mindset. Click-throughs or direct conversions to sale are very bad measures. Nice if it happens, but it shouldn't be the purpose of an ad. How often do you think newspaper ads get clicked on? I think they more often get a coffee mug put on top of them. Yet considering so many ads are bought in news papers, they do seem to be worth the cost.

Same for web ads. It's the impressions that count. It's that people get to see your logo, get to see your product, so that later when they're in the shop they go for the brand that they've seen many ads of, the brand that they know, over some no-name brand. That no-one clicks on them is totally irrelevant.

The only exception is Google's ads - I'm seeing those ads as glorified commercial search results. If I want to buy a product, the ads are what I'm looking at, as that's often companies that are indeed selling the product I'm looking for. If I want general information about that product, I ignore the ads but go for the organic results instead, which tend to be more review sites and the like, which do not sell the product I'm looking for.

How about: certain strains of bees happen to have natural resistance against the neonicotines.

The colonies that lacked this mutation have by now all died off (the exposure is so high that it takes just a few years for this to happen), leaving only those colonies with resistance, and those are now of course expanding rapidly: in part because there is more room, in part because people are helping them grow faster as there is a commercial need for it.

I thought recoil only happens the moment the bullet leaves the barrel, and as such recoil has no effect on accuracy. The more impressive thing is that the drone handles the recoil without breaking apart or being smacked into the ground, instead it handles it quite gracefully.

In many cases, the full circumstances of an event make the difference whether a law has been broken or not.

Were there any license requirements for things like flying the drone, owning the gun, firing a gun from a flying platform? Was that drone allowed to carry any cargo?

Where did it happen exactly? It may make a difference whether it's private land, public land, a gun range, or maybe a nature reserve.

It is not that black and white. So many possible questions may be raised which may determine that an act is legal or illegal.

Example. If you see something happening, it may be legal, it may be not. If you see a house being built, you will probably assume it's legal for those people to build their house there. But maybe it's not. Maybe on that piece of land, nothing is allowed to be built. Maybe they don't own the land. Maybe the building is not up to code. Maybe it's bigger than allowed. So many circumstances where building a house is legal, so many circumstances where building a house is not legal.

Another example. Grabbing a gun and firing it is, afaik, in general legal in the US. However doing so a busy street I suppose not legal. Aiming it at someone and then firing it, is also usually illegal - note the "usually", there may be moments it is legal, and then again it matters whether you're say civilian, military or police.

They probably check what's passing through the upstream filters, and is handled by a spamfilter.

My spam filter catches some 45-50 spams a day. It misses those with attachments (irritating - get 5-10 of those daily) and a few others that are hard to classify as spam (rather legit business related but not my business), but overall doing a decent job. I'm getting a similar number of legit mails a day, a large number of those being stuff like meetup and facebook status messages. So that'd be indeed about half/half for spam vs ham.

However, that 45-50 spam a day is AFTER greylisting, which basically requires every first-time sender (FROM, TO, source IP) to retry 5-30 minutes later. Many spambots just don't. I have this active for years, and when I installed it the amount of caught junk went down from some 300 a day to 30 a day. If this 10-fold difference is still the case, I'd be getting some 450-500 spam a day, or a 90% spam to 10% ham ratio. I'm not about to switch off greylisting to try this out, though:-)

How to measure (and slow down) sending rates of some bulk mailer, who sends e-mail to hosts all over the world?

The source doesn't have to follow the protocol - they just send out as fast as they can. The destinations (plural - probably big big numbers) have no idea what other destinations get from that source. Most of them will see just a few e-mails come in, that's their share. All the spammer has to do is not send everything for Yahoo at the same time, but intersperse it with mails to other destinations and Yahoo doesn't throttle him - or maybe Yahoo does throttle, but that won't stop the spammer from targeting other destinations in the meantime. They probably do that already, simply by having hundreds of outbound smtp sessions running at the same time.

You mean - just like human drivers are tested in various conditions, like dry sunny weather, during heavy rain, with ice and snow and at night, just to make sure they perform well under those conditions?

Rear-ending is something that always comes up in/. discussions about driving, especially by US drivers (the site is rather US centric). Everyone and their dog seem to have been in at least one such accident. I have never been in such an accident, nor have I heard of any European friends that had such an accident.

Add to that, statistics show that US drivers have far more accidents, injuries and deaths per distance (per km or per mile, whatever you like to use) than European drivers, especially those from western European countries. This while US streets are wider and straighter; quite some Americans are scared stiff by our narrow, winding roads - we're routinely doing things like driving 80 km/hr (the legal limit) on country roads, and not slowing down for oncoming traffic while the road is so narrow there's not even a line in the middle... because the road simply is plenty wide enough for two cars.

When self-driving cars can negotiate in bad weather conditions (i.e. ice, snow, slush, etc.), that's when I'll buy into your future. There is a reason why Google chose relatively warm, dry areas with typically good weather. Bad weather and poor roads makes things 100x harder for self-driving cars. Not to mention the ability to handle out of ordinary conditions or events. Figure these out, then get back to me about giving up manual driving. Until then, it's a mote point....

Interestingly you don't mention how much harder bad weather conditions make driving for human drivers, as well. There is a reason that many more than usual accidents happen when the weather is bad, when it's snowing, late at night (sleepy drivers - never heard about a robot getting sleepy), or when the roads are bad and human drivers think they know it all and can continue at top speeds.

Of course they start in good weather - that's also how you got your driving lessons. First make sure you can handle the good weather situations, then add bad weather into the mix.